An insert for a mould for vulcanising tyres for vehicle wheels, the insert arranged to receive in a seat formed on a moulding surface of the mould and comprising a base surface from which a plurality of projections extends; wherein, each projection comprises a lateral surface extending away from the base surface such that the lateral surface defines a tapered profile of the projection away from the base surface, is inclined at an angle between 10° and 25° with respect to a direction perpendicular to the base surface, and has a roughness between 4 and 11 μm.